hi i am now at a point where i should add some shadow to my engine.. i never uses any mass shadow like i need here (at moment the trees ars decals ,in final the closer ones are 3d models (and much relaistic ones,even the decals) ) the map is 300x300 blocks, so a very large shadow map over it wont look nice how can i handle this?

The sky is a simple Skybox with a large panorama Textur on it

The Grass are Decals
(at moment only one kind of grass,later i add more
plants,rocks etc to it to make it a bit realistic)


The Trees are at moment only a 2d bitmap
i take when trees ready 2 screenshots of the 3d tree
(north + west side)
and use it for far distance trees ..all in near then will be
shown as 3d modell ( i take about 20different trees at end)

Well you have a load of options depending on the structure of your game / engine. If your light is static, then you can create shadows for all static geometry (terrain, trees maybe too) in an offline process and store that information in a light map.

If your light is dynamic in one axis over time (such as the sun rising and setting) you can do really nice soft shadows by using occlusion interval mapping (see the nvidia gas station demo for a good example).

For dynamic objects, you either need to be using perspective shadow maps or stencil shadows really. There's loads of information around about which might be the best to use, and how to implement both of them.

Looking at your screenshots, if I were you I'd start with generating light maps for the terrain using the trees to cast shadows too. Then I'd use shadow maps (one per helicopter? Depending on how may choppers you have) for the choppers.

Hope this helps.

we try to make an massive multiplayer..

there will be a lot of player and vehicles sometimes
at same area...
(we got a lot of helicopter,tanks,jeeps,trucks...)

and destroyable Houses (like in old UFO/Jagged alliance games)

yes..the light is dynamic

ok,i try to work with a light/shadowmap for the large amount
of trees (about 5000 around every time, the landscape load
dynamic the parts when leaving the scene)
the simplest funktions may be the best..cause i cant
only look at quality of graphic at mmo's when
a lot of players start a raid..i have to use some tricks
(the water is not bump mirror...its voxel ;)